Chemical Reactions

Two Elements or Compounds yield to make one compound.

A + B → AB

Examples
Ca(s) + O2( g) → 2CaO(s)

Involving compounds:
SO3(g) + H2O(l) → 2SO4(aq)
CaO (s) + H2O (l) → Ca(OH)2 (aq)

One compound breaks down into smaller compounds or elements

AB → A + B

When a fuel which is often hydrocarbon, reacts with oxygen producing oxides, water and sometimes solid carbon

Complete: When their is excess if oxygen available to react with the fuel
Produces only carbon dioxide and water vapor
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Example: CH4 (g) + 2O2 (g)→CO2 (g)+2 H2O (g)

Incomplete Combustion: When there is limited amount of oxygen available to react with fuel
produces multiple possible carbon products (parts of carbon dioxide and water.
▲
Example: 2 CH4 (g)+3 O2 (g)→2 CO (g)+4 H2O (g)

One element in a compound is replaced by another element usually the metals replacing each other.
One element has to be higher on the activity series than the other to be able to displace it

A + BC → AC + B

Examples:
Fe (s)+CuSO4 (aq)→Cu(s)+FeSO4 (aq)
Cu (s)+ NaBr2 (aq)→no reaction
Cu is less Reactive than NA

This is the exchange of cations between two ionic compounds
Not all compound will be able to react it must be able to create a new substance

AB + CD → AD + CB

Examples:
BaCl2 (aq)+(NH4)2 SO4 (aq)→BaSO4 (s)+2NH4Cl (aq)
Insoluble
forms a ppt

FeCl3 (aq)+ Na2SO4 (aq) ⇾ No Reaction!

If it were to react both compounds are soluble therefore no new substance would be formed

Neutralization
An acid and base react to form an ionic compound and water

Examples:
NaOH (aq) +HCl (aq)→NaCl (aq) +H2O (l)

Chemical Equation:
A short form to represent chemical reactions

Reactants → Products

MAke sure to state the state of the element at room temperature

In a balanced equation there has to be equal numbers of each kind of atom on both the left and right sides of the equation (Law of Conservation of Mass) which states that mass can not be created or destroyed but transferred

Example of balanced equations:

NaOH (aq) +HCl (aq)→NaCl (aq)+H2O (l)
BaCl2 (aq)+(NH4)2 SO4 (aq)→BaSO4 (s)+2NH4Cl (aq)

Valence Oxidation Number

Rules:

1. Ionic bonds valence represents charges of ions when that are formed



2. Covalent bonds Valence represents how many electrons the atoms will contribute to to the bond (Sharing)

Covalent Compounds

Non-metal + Non-Metal

1. Use name of the first atom with prefix (except mono)

2. Add -ide to the stem of the second atom with prefix

Use Prefixes represents the number of atoms:
mono = 1
di = 2
tri =3
tetra = 4
penta = 5
hexa = 6
hepta = 7
octa = 8

examples:
dihydrogen monoxide = H₂O
nitrogen monoxide = NO

Ionic Compounds:

Metal + Non-Metal-ide

examples:
NaCl: Sodium Chloride
LiF: Lithium Fluoride

Multiple Valences:

Transition metals sometimes have more than one valance

ex. Fe+2 , Fe +3

Roman Numerals represent Valence:
I = 1
II = 2
III = 3
IV = 4
V = 5
VI = 6

Naming:
Metal (Valence # in roman numerals) + Non-metal-ide

Latin Prefix:

Latin prefix can be used to indicate the metal involved

Antimony=stib-
Chromium=chrom-
Copper=cupr-
Iron =ferr-
Lead=plumb-
Tin=stann-

Transition metal higher valance -ic
smaller valence -ous

examples:
FeCl₂ = Ferrous chloride
CuBr = Cuprous bromide

Binary Compound

If H is least EN write Hydrogen

If H is most EN change ending to ide

examples:
HCl: Hydrogen chloride
NaH: Sodium hydride

Oxy Acids
Polyatomic radicals bound to Hydrogen
change the ending -ate to -ic

example:
HClO3: Chloric acid

Oxy acids ending changes when the number of oxygen atoms increases or decreases


1 less oxygen: -ous
2 less oxygen: -hypo_ous
1 more oxygen: -per_ic

examples:
HClO4 (aq): perchloric acid
HClO (aq) : Hypochlorous acid

Acid Salt:
when H+ joins a polyatomic ion and reduces the charge by 1 each H+ added.

Add Hydrogen in front of the anion name(polyatomic)

examples
HCO3-: hydrogen carbonate
H2PO4-: dihydrogen phosphate
Potassium dihydrogen phosphite: KH2PO3

Peroxides
Peroxides have one more oxygen than a normal oxide O2 -2

examples:
Na2O2: Sodium Peroxide

Compounds when S replaces O use the prefix Thio

H2SO4: Sulphuric Acid becomes H2S2O3: Thiosulphuric Acid

Polyatomic Ions

Memorization tool:

NICK the CAMEL ate a CLAM for SUPPER in PHOENIX

Nitrate: NO3-
Carbonate: CO3 -2
Chlorate: ClO3- (Halogen pattern)
Sulfate: SO4-2
Phosphate: PO4-3

Other Polyatomic:
Acetate C2H3O2-
Cyanide CN-
Peroxide O22-
Ammonium NH4+
Hydroxide OH-

Polyatomic Ions ending changes when the number of oxygen atoms increases or decreases

1 less oxygen: -ite
2 less oxygen: -hypo_ite
1 more oxygen: -per_ate

examples:
KClO4: Potassium perchlorate
HBrO: Hydrogen hypobromite

Bases:
Bases will create hydroxide ions OH-

Following ionic rules:

examples:
Mg(OH)
Copper (I) hydroxide: CuOH

Writing Chemical Formula

Composition of Chemical Formulas:

1. Uses the elements that compose of the compounds.

2. Number of elements in the compound

3. Less EN element goes first in equation and the most EN equation goes at the end of the equation

examples:

Li₂O NaCl

Criss Cross Rule:

1. Write the symbols in order from Least EN to most EN

2. Write the charges on the top of the element

3. Cross the charges

4. Reduce if possible

examples:
MgS

Mg2+ S2-

Mg₂S₂

MgS